Neato! This is definitely a very interesting mix of photography and drawing. I think you did a good job on the composition and deciding where to position the characters. It's also pretty cool how the background is on the blurry side, although it's a motion blur (right?), it actually prevents the background from overpowering the characters. Also looks kinda painterly.

The only thing I might recommend is to maybe try fiddling with the background colors a wee bit. Are they exactly true to life? It might be worth adjusting the contrast or even tinting the BG, so that the colors integrate with that of the characters a little more. Also, I'm really impressed how you inserted the characters so smoothly, without any jagged edges or 'green screen' effect. And the figures are really well drawn too. Keep up the good work ^_^